Want to know how to solve this

tan( angle )  =  opposite / adjacent

tan( 30° )  =  9√3 / PQ

PQ tan( 30° )  =  9√3

PQ  =  9√3 / tan( 30° )

PQ  =  27

....Or.....you can notice that this is a 30-60-90 triangle. And remember in every 30-60-90 triangle,

side opposite the 60° angle  =  √3 * ( side opposite the 30° angle )

PQ  =  √3 * 9√3

PQ  =  3 * 9

PQ  =  27

Oh, that's what I should have done! I messed up. Thanks, hectictar.